What spell does bellatrix in Harry Potter 6 use on hadrigs hut?

Bellatrix Lestrange doesn't use a spell on Hagrid's Hut in Harry Potter and the Half-Blood Prince. She and the Death Eaters attack the house in search of Harry Potter, but they do not cast any specific spells on the hut itself.

The most notable destruction of Hagrid's Hut occurs in Harry Potter and the Deathly Hallows, when it is burned down by the Death Eaters.